1. Field of the Invention
This invention relates to a torch tip for burning a fuel with an oxidizer. The invention is particularly directed to a multiple burner torch tip for mixing fuel with air and burning the resultant combustible mixture in a plurality of burners located in a burner head at the end of the torch tip.
2. Description of the Prior Art
This invention is an improvement over assignee's U.S. Pat. No. 4,013,395 to Wormser entitled "Aerodynamic Fuel Combuster." In the prior art patent to Wormser, an improvement in torch tips was provided. The Wormser invention provided a dramatic improvement in performance for oxidizer/fuel torches. The prior art Wormser invention includes a flameholder in the form of a vortex generator having one or more flow channels to provide swirling gases to a combustion chamber. The flow channels are constructed so as to impart a swirling motion to the burning gases, which are centrifuged to the outside walls of the combustion chamber, thereby cooling the chamber walls. The flameholders include bluff body means for causing eddying turbulent flow which enhances combustion.
The combined swirl and bluff body effect produced by the flameholder is twofold. First, it provides flameholding with less pressure drop than for only swirl or only bluff body flameholding. Second, it permits higher gas velocity within pressure drop limits imposed by the air injector. This higher gas velocity provides: (1) enough combustion air for a stoichiometric mixture which provides the highest flame temperature and also permits complete combustion within the combustion chamber without need for outside air, and (2) better heat transfer from flame to work because of the higher velocity with which flame impacts the workpiece.
This stoichiometric mixture is not only more efficient because the fuel is completely burned, but also because it resists blowout. Prior conventional torches use an air/fuel mixture which is fuel rich. This reduces the velocity of the gas through the torch so as to prevent blowout. To ensure complete combustion, these prior art torches utilize a secondary combustion with ambient air at a location downstream of the burner. Such secondary combustion is undesirable because it reduces flame temperature as the ambient air cools the flame. The result is that the heating effectiveness of such prior art torches is substantially reduced. The Wormser torch resulted in achieving higher flame temperatures than with prior art secondary combustion torches.